1. Field of the Invention
This invention relates generally to temperature responsive valves and more particularly to a temperature responsive valve for controlling fluid flow including a bimetallic snap disc which is operable in response to the temperature of a separate controlling fluid surrounding the valve.
2. Prior Art Description
Conventionally, a temperature responsive valve construction comprising a housing having open and closed ends, a valve body sealingly inserted into the housing to define a chamber between one end thereof and the closed end of the housing, inlet and outlet passages provided within the body, a valve seat member disposed about either the inlet passage or the outlet passage, a bimetal member engaging or disengaging the valve seat member by snapping over center, being held outer periphery portion thereof against the outer periphery portion of the one end of the valve body, in response to the temperature of the external fluid surrounding the housing for controlling the fluid communication between the inlet and outlet passages, and a leaf-spring disposed within the chamber for holding the outer periphery portion of the bimetal member against the outer periphery portion of the one end of the valve body by the biasing force thereof is well known.
This type of the valve construction, however, has drawbacks that the bimetal member tends to mis-snap over center due to engaging the one end of the valve body in assembly, and furthermore, the setting position of the bimetal member to the leaf-spring tends to shift from the predetermined position, whereby the fluid communication between the inlet and outlet passages is not controlled even if the temperature of the external controlling fluid is changed and the bimetal member tends to snap over center in unexpected temperature because of the change of the load characteristic on the bimetal member, because this type of the valve construction is assembled in the manner that the leaf-spring is put on the predetermined position within the housing, the bimetal member is slidingly fitted to the predetermined position on the leaf-spring, the valve body is inserted into the housing so as to engage the outer periphery portion of the one end thereof with the outer periphery portion of the bimetal member and the housing is secured to the valve body by caulking the open end thereof.